Rosario was convicted after confessing that he and two other men had used Molotov cocktails to set the fire, the deadliest in Lowell’s history. But for three decades he has steadfastly denied his guilt. Twice before, he has sought a new trial and been denied.

In vacating the sentence, Tuttman said Rosario’s defense had produced new evidence that “calls into serious question the voluntariness of his confession.”

In her decision Monday, Tuttman cited evidence that police coerced Rosario and that he was suffering from alcohol withdrawal during his confession.

At a March hearing, a fire specialist who reviewed Rosario’s case said evidence originally interpreted as proof that the fire was set intentionally was equally consistent with an accidental fire.

After leaving the courthouse, Rosario went to give thanks.

“The very first thing was to go to the church that has been such a rock for him and for his wife, the Tremont Temple Baptist Church,” Kavanaugh said in a phone interview Thursday.

Rosario now plans to live in Brighton with his wife, Beverly, whom he met through prison English classes she taught, but his freedom could be short-lived. Prosecutors said they would seek to retry him.

Assistant Middlesex District Attorney Thomas F. O’Reilly said in court Thursday that the evidence “strongly suggests” Rosario was responsible for the blaze and that his confession “coincided with what witnesses said they saw.”

“The fact of the matter remains: Eight people died,” O’Reilly
said.

On Wednesday, Harold Waterhouse, a lead investigator in the original case, stood by his conclusions, despite new expert testimony that cast doubt on whether the fire was arson and whether the type of Molotov cocktails Rosario allegedly used were powerful enough to ignite such a large fire.

In arguing for bail, Kavanaugh said Rosario would probably prevail on appeal.

Kavanaugh said that Rosario had a sterling record as an inmate, with no history of violence, and that he was not a flight risk.

“He has absolutely no reason to flee,” she said.

She said later that much work lies ahead to clear Rosario’s name, but for the moment, he was “full of joy and hope” and looking forward to life outside prison.

“I think he wants to go for a run,” she said. “He’s a runner. It’s one of the many things that has helped him get through.”

By chance, Rosario’s release fell on the same day as a disastrous fire in Lowell that killed four adults and three children, making it the deadliest fire in Massachusetts in two decades.